As the final demand is the proportional relation between speed outputting from gear box and square signal, not the corresponding relationship between armature and squaresignal. Magnet motor (63,77) can mount with encoder system whichdeveloped by our R&B. This encoder system can output one or two phases square wave in direct ratio to armature speed, in which two phases square waves can supply control sub-unit different phase relation to recognize the positive and negative rotating.